Modern communications systems use optical fibers to replace wire cables. In order to connect optical fibers together, a wide variety of connectors and adapters have been developed and are well known in the art. These connectors and adapters have taken on a wide variety of shapes and sizes, but common among them is the need to provide for uncontaminated optical connection surfaces and precise alignment between optical fibers that are to be coupled.
A common technique for connecting optical fibers is by terminating an optical fiber with a ferrule, and bringing the ferrule into a mating relationship with another ferrule terminating a second fiber. The ferrules are precisely aligned by a cylindrical sleeve which typically receives two ferrules of similar size and coaxially aligns the longitudinal axis of the respective optical cores thereof. The sleeve and a sleeve housing are typically components of a coupler or adapter which securely couples together the plug housings of the respective optical fibers. Examples of such connection systems can be found in U.S. Pat. Nos. 4,738,507 and 4,738,508, both issued to Palmquist and assigned to the assignee of the present invention.
A problem that is encountered when terminating optical fibers is that the fiber ends may be damaged by adverse environment hazards, particularly in the case of an unconnected fiber. In particular, dust and dirt as well as external contact with the fiber may contaminate or damage the optical fiber and thereby impair the optical transmission capabilities of the fiber.
Consequently, when an optical fiber is not in use or is not connected to another fiber, it has been proposed to cover the end of the fiber to prevent dust and other debris from collecting on the exposed surface of the optical fiber or to prevent external contact therewith. For instance, it is known to provide a dust cover for the end of a fiber optic connector, adapter or other body associated with the connector. Such covers are typically used during transport or storage of the optical fiber connector or at other times when the connector is not in use.
For example, U.S. Pat. No. 4,640,575 to Dumas discloses a flexible flap used to cover a fiber optic connector so as to prevent emissions from the connector. The Dumas flexible flap allows forcible deflection of the flap area, so that a mating connector can be attached to the normally covered connector, and yet when the mating connector is removed, the flap will automatically return to the covering position. According to Dumas, in addition to preventing the emission radiations, the flap can reduce contamination materials, such as dust, from adhering to the end of the fiber optic material. Likewise, U.S. Pat. No. 5,202,949 to Hileman, et al. discloses a dust cover for covering one or more fiber optic ferrules of an optical fiber connector. The Hileman dust cover comprises a base portion and at least one protruding portion extending therefrom, the protruding portion having a cavity therein for receiving and covering the ferrule when the dust cover is mounted to the connector. The Hileman dust cover is used in connection with connectors having a retractable body portion which normally surrounds the ferrule when the connector is not in use.
A dust cover 2 for an LC buildout adapter, manufactured in accordance with the prior art, is illustrated in FIGS. 1-4. As the figures demonstrate, the LC adapter includes a base 4 and a cap 6 that removably snaps to the base 4. The LC type adapter is for connecting smaller diameter ferrules, which offer the advantages of being more proportional in size to the fiber optic cable for improved axial alignment and more space efficiency. In particular, the relatively smaller LC connectors and adapters can be more densely packed, at the face of a piece of network equipment for example, and therefore may provide more efficient space management. The dust cover 2 fits within the LC adapter to cover a ferrule sleeve housing 8 to prevent contamination of the optical fiber which fits within the sleeve housing 8.
While optical fiber dust covers of the prior art have generally met the basic needs expressed above, they have experienced a number of problems. In particular, prior art dust covers for fiber optic adapters, such as the LC adapter, have experienced problems of stability and alignment within the deep recesses that are typically present within optical fiber adapter bodies. These deep recesses also often cause problems of placement and removal of the dust covers. When the stability and alignment problems are combined with the placement and removal problems associated with dust covers, the prior art dust covers are often misaligned within the adapter bodies, damaging the dust cover, sleeve housing and the optical fiber.
Accordingly, it would be desirable to provide a fiber optic adapter dust cover that easily functions in adapter caps or bases. It would also be desirable to provide such a dust cover that is accessible in panels having deep recesses and prevents misalignment of the dust cover within the adapter cap or base. Such a dust cover would not only prevent damage to the dust cover itself, it would ensure proper mounting of the dust cover within the adapter assembly, be a prophylactic to contamination of the optical fiber, and protect the sleeve housing and optical fiber from damage.